photography by sofie kirk
A new study by Lassonde School of Engineering Professor John Moores has found evidence that snow and ice features previously only observed on Earth have been spotted on Pluto.
Penitentes are bowl-shaped depressions formed by erosion, with spires around the edges that measure several metres high. They are found at high altitudes on Earth. Moores’s groundbreaking research, done in collaboration with NASA and Johns Hopkins University, indicates that these icy features may also exist on other planets where environmental conditions are similar to ours.
“The identification of the ridges of Pluto’s Tartarus Dorsa as penitentes suggests the presence of an atmosphere is necessary for the formation of penitentes, which would explain why they have not previously been seen on other airless icy satellites or dwarf planets,” says Moores. “Exotic differences in the environment give rise to features with very different scales. This test of our terrestrial models for penitentes suggests we may find these features elsewhere in the solar system, and in other solar systems where the conditions are right.”
Moores and his colleagues compared their model to ridges on Pluto imaged by the New Horizons spacecraft in 2015. Pluto’s ridges are much larger – 500 metres tall and separated by three to five kilometres – compared to their metre-sized cousins on Earth.
Moores says Pluto’s penitentes’ gargantuan size is predicted by the same theory that explains the formation of these features on Earth. Researchers were able to match the size and separation, the direction of the ridges, as well as their age – all of which was evidence to support their identification as penitentes, he says.
Although Pluto’s environment is very different from Earth’s, Moores says the same laws of nature apply.
Both NASA and Johns Hopkins University were instrumental in the collaboration that led to this new finding. Both provided background information on Pluto’s atmosphere using a model similar to what meteorologists use to forecast weather on Earth. This was one of the key ingredients in Moores’s own model of the penitentes, without which they would not have been discovered.